Wireless telegraphy.



R. A. PESSENDEN.

WIRELESS TELEGRAPHY.

APPLICATION FILED JAN.29,1910.

Lflfifig 1,, Patented Nov. 26, 1912.

/46 i @fiE-Affi g; F149 a anemia g Parana carton REGINALD A. FESSENDEN', OE'BBANT. BOOK, MASSACEUSET'ES,. ASSIGNOE T0 NATIONAL.

ELECTRIC SIGNALDIQ comm. 0E BITTStBUBG-E, BENNS'ZLVANm A. CORPORA- .EION OF NEW I wmnrnss TELEGRA-PHY.

.Ltld5-JZ81.

Original application flied: June. 16;. 1%8;

Specification of Letters Patent.

semi an exam. mvidmhandz Waa auamanisd January as, 19530. Sextet N01 norm Eaterated Nov. $6, 1912.

ing by electromagnetic waves, and its p11-' ma object is to provide amore eilicient receivmg device for signals so sent.

This application is a division of my copending application No. 438,725, filed June? 16th, 1908.

In the accompanying drawing F1 re 1 1sa side view of a recelver for pro ucing a. visible signal, and Fig. 2 is a plan of the same. Fig. 3, shows a side view of a modified form of electrostatic receiver producing a change in a local microphomc circuit- Fig. 3 is apartial vertical section and diagram of an amplifier 0r relay. Fig; 4 1s asimilar view of a modified form: in which pressure efl ects are balanced and operate differentially to produce a more sensitive instrument. I

A static telephone receiver as described by- Dolbearin his United States Patent No. 350,299 of 1882, has been used in various forms, with the diaphragms made of sheet metal either plain or covered with an electrified dielectric, or else made of a dielectric with a metallic coating on the side next the .fixed plate. These types of receiver, however, have been insensitive and have not come into practical use. I have discovered, however, that by the use of certain improved constructions and methods of operation, static receivers can be made extremely sensitive, and I here show a form of such receivers.

For example, I have found that if a thin conducting film such .as oldleaf, be coated with insulating materia and kept in relative motion in contact with another surface, the friction is greatly altered when the conducting film 1s electrified. Therefore as shown in Fig. 1, I make use of this phenomenon by providing a wheel 146 with a conducting surface such as finely burnished nickel steel or platinum iridium, which may be driven by any convenient means at uniform speed, and in revolving dips into a bath such as a tank of lubricating oil 147,

whereby the lubricant is carried over the wheel and forms a thin film thereon. A

light film: of aluminum or gold 1 48' rests thereon.

(For use with aluminum I found -milk' to" be a suitable lubricant). This gold or aluminum: leat 148 is connected' by a filament 148- toa siphon arm 14. 9, supported in i any convenient way as by bifilar' suspension 150', dipping into an. ink well 1511 and its discharge end resting on traveling paper 1 152 driven by ulleys or any other usual -way'. It will e understood that theaxle 3 153 of. the wheel 146 is electrically connected as by a brush 154'to a terminal 155 coninected with an oscillating circuit, while the otherterminal 156, may be connected by a flexible lead? 157 to any convenient point on T the leaf 148.1

In operation, the impulses received from an antenna or other circuit at one of the 'terminal's155, 156, charge the leaf 148 and f the wheel 1461 through the medium of the separating-film" (if-lubricant. This charging produces an increased frictional drag be tween the relatively moving parts, (probably on account of increased pressure between the surfaces, 111 part, though it appears that thereare other obscurecauses unr 1 ecessary to mention). The increased fric-,, .tionof course. acts to move the leaf 148' and therefore moves the pointer of the recorder 149,- making a written signal as shown in of the mica leaf is controlled by a fine fiber 162 which is mounted for adjustment of tension on a bolt 161. The other end of the mica leaf may be connected by fine filaments 164 to a plate 94 which is mounted pivotally on wires 101 and has one end dipping into a trough 97 containing granules of carbon and having electrodes 98 and 99 connected to a local signaling circuit, the whole device forming a relay as indicated in Fig. 3 ,-it being understood that thebattery circuit has one terminal connected to the plate 94. Thus the movements of the electrostatic leaf 159, 160, will inovethe plate 94, vary its position and pressure in the "trough of microphonic carbon and thereby vary the current in the local battery circult and effect the telephone T, as will be evident to those familiar'with the art. Of course, any other form of amplifier or relay could be used in place of that shown in Fig. 3, or any other 'device for apparent the eaf movements of the electrified 160, but I have found this form of relay extremely sensitive.

In'Fig. 4,-I have shown a modified form" of receiver and-recorder in which I employ two revolving disks 158 and 158*, each having a mica strip and gold leaf as in Fig. 3. lhis being as before connected to live terminals 165, 166, on the one side, and 167,

- 168, on the other. The leafs are supported as before by filaments 162 and 164, but in this case all the filaments 164 are connected to the arm of the siphon recorder 149 as in Figs. 1 and 2. By this means, I get a difj conductin ferential effect by the balanced tensions of the traction elements, by adjusting the phase of the oscillations through the two circuits .to act oppositely and this results in making by to change the tween them, and maintained in r tively movable conductors maintained -in frictional relation through the medium of an intervening dielectricmeans for electrostatically chargin said members, wherecfiegree of friction, and means for recording the resulting change of relative position of said conductors.

3. An electrical indicator comprising two pairs of relatively movable conducting members in frictional relation to each other through the medium of an intervening dielectrlc, a recorder connected to said pair of conductors so as to be acted on differentially .by their tractive forces, and means to produce an electrostatic field of force. between the members of each pair of conductors, whereby changes in said electrostatic forces are recorded by the combined effect on the recorder, substantially as described.

4. The combination with terminals connected to a source of oscillating currents, of a pair of relatively moving conductors having an intervening dielectric and constituting 'a condenser with relatively moving members in a state of frictional traction,-

and means to indicate the relative change of position of said members of the said condenser when the fi'ictional traction is altered by change of strength of the electrostatic field between them produced by said oscillating current, substantially as described.

In testimony whereof I have hereunto signed my name in the presence of the two subscribed witnesses.

, REGINALD A. FESSENDEN.

Witnesses: Jnssm ETTA BENT,

FLORENCE MAY LYON. 

